One of Scotland’s top psychologists has challenged the idea that Adverse Childhood Experiences (ACEs) are a major cause of bad outcomes leading to issues like addiction in adult life.

Dr John Marshall, a consultant forensic and clinical psychologist who assessed the teenage murderer of six-year-old Alesha MacPhail, says many sports stars, artists and actors who had traumatic childhoods go on to thrive.

His opinion runs contrary to what he describes as the “dominant discourse” in Scotland where there is an acceptance by the Scottish Government, teachers and social workers that ACEs may disturb brain development. He also believes this orthodoxy has placed an unrealistic burden of responsibility on parents.

The concept of ACEs is based on a US study carried out on 17,000 Californians between 1995-1997, which found that as the number of traumatic experiences in childhood rose, so did the incidence of depression, alcoholism and suicide attempts in later life.

However, Marshall says science has yet to prove any causal link between ACE experiences and poor health. He argues that those who champion the study of ACEs struggle to answer the basic question of why two individuals who have similar traumatic childhood experiences, such as physical beatings or sexual abuse, go on to have different life outcomes as adults.

Speaking to Scotland on Sunday, Marshall asked: “What do musical virtuoso Dizzy Gillespie, the inventor of Bebop jazz, Jonah Lomu, arguably the greatest All Black rugby star, and pioneering artists like Salvador Dali all have in common? They all suffered considerable ACEs, but their ACEs scars also drove them on to excel. ACEs on their own do not sufficiently explain abnormal development and the interplay between environment and genetics. Why does one person fold into a life of crime and addiction and another become a high-functioning thriver with the same ACEs?”

Marshall said he has felt duty bound to speak out, claiming colleagues have been sidelined for challenging the theory of ACEs.

He added: “Making tough parenting decisions with the limited resources you have, being present, providing security and stability show that love is not enough to be a good parent… Often relationships are an ominous prospect for people with ACEs and complex trauma. Developing therapeutic relationships is important in psychotherapy but simply taking this ‘relationship’ approach alone is not likely to lead to clinical change.”

But Dr Suzanne Zeedyk, a psychologist and expert on childhood trauma, challenged Marshall’s analysis. “I disagree with Dr Marshall,” she said. “We don’t need to wait for more research. The core message from 20 years of ACEs science is that responsive, stable, trusting relationships buffer children from stress that could otherwise become toxic.

“Scotland is getting this message about the importance of supportive relationships. Over the past two years, tens of thousands of people have been inspired by the idea of an ACE-Aware Nation. That is prompting new thinking about criminal behaviour, addiction, homelessness, the structure of the care system and the causes of poor attainment. Scotland has the highest rate of drugs deaths in Europe. One-third of prisoners were in care. A quarter of our children live in poverty.

“ACEs has given us the curiosity to ask how these issues might be related. It’s strengthened our courage to see the suffering that too many of our children endure, right in front of our eyes.